Direct-reading burette



n A. M. JACKSON. DIRECT READING BURETTE.

APPLICATION FILED JULY 29| '|920- hmmm-xu. 2,1921.

IIIIIIII ALBERT M. JACKSON, 0F LOS ANGELES, CALIFORNIA.

DIRECT-READIN G BURETTE.

vApplication mea July 29,

T o all whom it my concern:

Be it known that I, ALBERT M. JACKSON, a citizen of the United States, residing at Los Angeles, in the county yof Los Angeles and State of California, have invented new and useful Improvements in Direct-Reading Burettes, of which the following is a speci- 'cation.

This invention is a direct reading burette and has for its object the provislonl of a graduated slide longitudinally adjustable relative to the burette and arranged to directly measure variations in volume within the burette.

It is a further object of the invention to provide a slide of this character which may be accurately adjusted to compensate for variations in the uniformit of the capacity of the burettelongitudinalliy bf the same-` The invention will be readily understood from the following description of the accompanying drawings, in which Figure 1 is a side elevation of a burette before mounting the graduated slide upon the same.

Fig. 2 is -a similar view showing the slide upon the burette.

Figs. 3, 4 and 5 are similar views showing the successive steps in determining the variations in uniformity of capacity of the burette at the upper end thereof.

Figs. 6 and 7 are similar views showing the method of determining the variations of capacity at a point along the burette spaced from the end thereof.

Fig. 8 is a similar view showing the capacity variation indicating line upon the burette.

Figs. 9 and 10 are similar views of the burette with the slide thereon,the parts being graduated for use and showing the `successi-ve steps in using the burette. i

Fig. 11 is a side elevation of the graduated slide.

Fig. 12 is a perspective view of the retaining clip for releasably securing the slide in adjusted positions along the burette.

The burette consists of the usual tube 1 having the nozzle 2 at its lowerend controlled by the pinch cock 3.

A slide 4 shown as atransparentl sleeve is received over the burette and is arranged to be longitudinally adjustedalong the burette. The slide is, preferably, releusably retained in adjusted positions by means of Specification of Letters Patent.

Patented Aug. 2, 1921. 192e. serial No. 399,960.

a spring clip 5, preferably, split as shown at 6 and adapted to yieldabl engage the burette below slide 4 so as to orm a support for the slide relative to the burette.

Graduations 7 are formed upon the slide and are arranged to measure variations in the cubic contents of the burette as determined by the variations in level of the contents of the burette.

'I he graduations 7 are, preferably, longitudlrially alined along slide 4 and 'are shown as transverse lines upon said slide. These lines are angularly disposed relative to one another as radii from a common center A beyond the slide and as indicated in Fig. 11.`

A reading line 8 is marked upon the b urette, said line being the usual .straight line extending the length of the burette. A notch 9 is formed in the upper edge of Slide 4, preferably, in longitudinal alinement with a medial line through the graduations 7. The slide is placed upon the burette with line 8 in alinement with notch 9, and the ,graduations 7 are positioned upon the slide so that the points at which said graduations cross the line 8 will indicate successive units of the measuring systemfor a burette of uniform cubic capacity. The measuring system employed is; preferably, cubic centimeters, and the slide is, preferably, graduated to measure 10 c. c.

In practice it has been found impossible to construct burettes of uniform cross sectional area throughout their lengths and as a conse uence when notch 9 is in alinement with ine 8 graduations 7 will not yacl curately measure the cubic contents of the burette lat various points along the latter where variations in the cross sectional area occur.

In order to compensate .for such variations in order that accurate readings may be obtained, the following arrangement 1s made: The burette is approximately filled and the; zero of raduations 7 is alined with the li uid leve with notch 9 in alinement wit line 8. This arrangement of the parts is shown in Fig, 3. By any measuring system known to be accurate, exactly 10 c. c. of the contents of the burette are withdrawn. If the portion of the burette upon which the slide ispositioned is of uniform cross sectional area, the intersection of the liquid level with line 8 will also intersect the gradnation oi the slide denoting 10 c. c. If,

however, the burette is not uniform in size' uid level with line 8 denoting the change in the c. c. graduation will not intersect the cubic contents. 50 crossing-of the liquid level andline 8. This By the construction as thus set forth it condition is shown in Fig. 4. Without shiftwill be seen that the slide is adjusted relaing the slide lengthwise of burette, the slide tive to the burette at points throughout its. is then rotated upon the burette until the 10 length in order that an accurate reading c. c. graduationcrosses theintersection of may be obtained upon the slide irrespective the liquid level and line 8. This position is of variations in the cubic capacity of the shown in Fig. d. The notch 9 will now be at l burette at various points along its length. one side of line 8 and the position of the Various changes may be made without denotch relative to the burette 'is indicated parting from the spirit of the invention as upon the latter by the pointl. claimed.

The slide is then shifted valong'the burette Whatl is claimed is: l

until the zero graduation crosses the inter- 1. The combination with a burette, of a section of the liquid level and line 8, the slide transparent graduated sleeve slidable longibeing also reversely turned upon the burette tudinally along said burette; so that notch 9 is again in alinement with 2. The combmation with a burette, havo5 line 8. This position is shown in Fig. 6. ing .a reading line extending .lengthwise of 'Exactly 10 c. c. of the contents of the burette said burette, of a member longitudinally and are then'withdrawn as' previously described, circumferentially adjustable with relation and if the 10 c. c. graduation does not cross to said burette and having graduations therethe intersection of the liquid level with 'line on inclined relative to sald reading line. 70 8, which condition islillustrated in Fig. 6, the 3. The combination with a burette, havslide is again turnedl relative to the burette ing a reading line extending lengthwise of until such crossing does occur, afs shown said burette, of a member longitudinally and in Fig. 7. f circumferentially adjustable with relation The off-set position of notch 9 relative to to said burette4 and having graduations there- 75 line 8 is indicated upon the burette by the on inclined relative to said reading line, said mark 11. In similar manner the oi-set pograduated member being rotatably adjustsition to which itA is necessary to turn slide able upon said burette, and means forguid- 4 in'order to obtain an accurate reading is ing said rotatable adjustment.

indicated by marks 12-13 etc. along the 4.' The combination with a burette, hav- 80,

lengthof the burette. A curved line 14 is ing a reading line extending lengthwise of then marked upon the surfaces of the burette said burette, of a member longitudinally connecting the oints 10, 11, 12, 13 etc. and circumferentially adjustable with rela- In use, when 1t is desired to measure a diftion to said burette and having graduations ference in cubic contents of the burette the thereon inclined relative to said readin line, slide 4 is turned relative to the burette and said. graduated member being rotatab y adis longitudinally positioned thereon so that justable upon said burette, and means for notch 9 is in alinement with guide line 14 guiding said rotatable adjustment arranged and the zero graduation of the slide crosses to cause readings by said graduations at the the intersection of the liquid level and linecommon intersectlon of ,said graduations 8. This position of the slide is shown 1n Fig. ywith the level of thev contents of the burette 9. If, now, a portion of the contents of the and said reading line.

burette is withdrawn, the diie'rence in cubic In testimony whereof I have signed my contents may be accurately read u on the name to this specification. slide, the crossing of one of the gra uations of the slide with the intersection of the liq' ALBERT M. JACKSON. 

